NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/NOAAscales - NOAA/SWPC.

INTERPLANETARY SHOCK
WAVE: A shock
wave moving through the solar wind hit Earth's
magnetic field on Feb. 16th at approximately 11:30
UT. The impact did not spark a geomagnetic storm.
Nevertheless, sky watchers around the Arctic should
be alert for auroras as Earth passes through the
wake of the disturbance. - Space Weather.

WEAK SHOCK DETECTED: The ACE Spacecraft detected a weak interplanetary shock at 10:58 UTC this morning. The solar wind increased to around 400km/s. A sudden geomagnetic impulse was detected by the Boulder, Colorado magnetometer at 12:10 UTC and measured 10nT. This signaled the passage of the weak shock past our planet. This particular event is not expected to bring widespread geomagnetic disturbances.

UPDATE: The Kp index is currently at 4, which falls just below minor geomagnetic storm levels. The solar wind remains near 400 km/s with Bz fluctuations from -11 nT to +7 nT. Visible aurora will be likely at very high latitudes.

Updated
image of the visible solar disk on Saturday morning. Sunspot 1671 and
new Sunspot 1673 remain fairly stable. A small new sunspot is forming in
the northeast quadrant, but is not yet a threat for strong solar
flares. Elsewhere, another sunspot trailing region 1673 is now beginning
to rotate onto the southeast limb. There will be a chance for isolated
C-Class flares.